Once you’ve found the right car seat for your child, you need to install it. Installing a child safety seat is harder than you might think. In fact, the National Highway Traffic Safety Administration reports that almost half of all car seats are installed incorrectly.

rear facing car seat
Correctly installed car seats keep kids safe and happy (U.S. News)

One way to help make sure your child’s car safety seat is installed correctly is to use the vehicle’s Lower Anchors and Tethers for Children (LATCH) system. LATCH consists of two anchors in the space between the seat bottom and seat back, as well as a top tether on the back of the seat, in the cargo area, or in the rear deck (the space below the rear window in a sedan). “Parents who use LATCH are more likely to install child restraints correctly,” says Jessica Jermakian, a senior researcher at the Insurance Institute for Highway Safety. “One way to cut down on installation errors is to use LATCH because parents are more likely to use them correctly.” Check out 7 Car Seat Mistakes that Put Your Kids at Risk to see installation and other car seat errors that parents make.

While LATCH has been required in all new cars since 2002, some LATCH systems are easier to use that others. The IIHS has created a rating system for LATCH systems that measures how easy they are to use. "LATCH is meant to simplify child seat installations, but it doesn't always succeed," says Jermakian. "Parents often struggle to locate the anchors in the vehicle or find it’s difficult to attach the seats to them. We believe fixing these problems will make the task less frustrating for parents and increase the likelihood that children will ride in properly installed seats."

To earn the top “Good” rating, a vehicle’s LATCH system must have lower anchors that are no more than ¾ of an inch deep in the space between the seat bottom and seat back, as well as a clearance angle of 54 degrees or less. Installing a car seat correctly with LATCH can be quite physical, so to earn a “Good” rating, the system must not need more than 40 pounds of force to attach the car seat to the lower anchor. Vehicles with a “Good” rating must have tethers in the top 85 percent of the back of the seat or on the rear deck, not on the cargo floor or vehicle ceiling. The tether must also be clearly labeled, or there must be no other hardware, like a cargo tie-down, that could be confused for the tether, in the area.

2015 Audi Q3 LATCH
A lower anchor in the 2015 Audi Q3 with a car seat connector attached. (U.S. News)

While the ratings look at how easy child safety seat installation is with LATCH, they don’t measure how well each LATCH system functions in a crash. As IIHS notes in a press release, “The ratings measure ease of use only. A correct installation in a vehicle with poor LATCH is just as safe as a correct installation in a vehicle with good LATCH.” Still, vehicles with LATCH that are easy to use make it more likely that parents will use the system, and more likely that their child’s restraints will be properly installed.

Only three vehicles, the BMW 5-Series, Mercedes-Benz GL-Class and Volkswagen Passat earned the top rating of “Good.” Forty-four vehicles earned a rating of “Acceptable.” A “Marginal” rating was earned by 45 vehicles, and 10 earned a rating of “Poor.” The ratings also take into account where the LATCH systems are placed in a vehicle. "Even if you're not in the market for a new vehicle, our ratings can be a helpful source of information about a vehicle you already own," Jermakian says. "We're essentially providing you with a map of where child seats can be installed most easily in your vehicle, including the specific hardware available for each seating position."

In the market for a family car?  Check out our 2015 Best Cars for Families. When you’re ready to buy, use the U.S. News Best Price Program for guaranteed savings on your new vehicle. Also, be sure to follow us on Twitter and Facebook.